Brix drifts down before adding yeast

[rhodesengr]

Working on my plum wine as usual but am curious about something I observe. When I set up my must, I add sugar to get whatever brix I am targeting; lets say 24. I've added K-meta and am waiting the usual 24 hours before adding yeast. I check my Brix again 12 hours later, and its lower; usually by 1 Brix or so. I haven't changed or added anything but I see the brix drift down over that initial 24 hours before adding yeast. I check Brix with both a refractometer and hydrometer. Is this drift real? Is the sugar disappearing (seems unlikely). Is the water concentration going up? Maybe yes if the pectic enzyme is breaking down the fruit cells. Anyone else see this? Is this a known thing?

 

[winechef]

Your sugar could have settled. stir and check again

 

[BPL]

Working on my plum wine as usual but am curious about something I observe. When I set up my must, I add sugar to get whatever brix I am targeting; lets say 24. I've added K-meta and am waiting the usual 24 hours before adding yeast. I check my Brix again 12 hours later, and its lower; usually by 1 Brix or so. I haven't changed or added anything but I see the brix drift down over that initial 24 hours before adding yeast. I check Brix with both a refractometer and hydrometer. Is this drift real? Is the sugar disappearing (seems unlikely). Is the water concentration going up? Maybe yes if the pectic enzyme is breaking down the fruit cells. Anyone else see this? Is this a known thing?

I have experienced he same thing. I'm not a chemist, but have a theory.... I make country wines and various varietals of "grape" wines. If the sugar content of the fruit pulp is different than the sugar content of the liquid (must), the balancing of the sugar will take place. The change takes place between the dissolved sugar in the must and the sugar content in the pulp. Pectic enzyme speeds up the process by breaking down the pulp. Just a guess, but makes sense to me.

 

[winemaker81]

The brix changing is normal. I did a test where I checked SG after assembling a must, and in the morning stirred again and re-checked the SG. Nine out of ten times, the readings were slightly different.

As stated above, the fruit macerating may cause the change, and it's likely the added sugar was not as well distributed as believed.

In larger batches I check the SG in 3 spots in the primary, and if the readings are not the same, I stir again.

 

[Hazelemere]

the plums have less sugar than your must. That is why SG drops.

 

[Ckent]

The drop in Brix before you add yeast is often due to the pectic enzyme breaking down the fruit and releasing more water into the must. It can dilute your sugar concentration a bit. It’s normal to see a slight change in Brix over that period, and it’s good you’re using both a refractometer and hydrometer to double-check. As long as the drop isn’t drastic, it’s usually nothing to worry about.